Difference between revisions of "Comsol/Troubleshooting"

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(Created page with "===Problems with the COMSOL 5.2 GUI=== We noticed, that in some cases, the COMSOL 5.2 GUI updates very slowly when staring it on Euler or sometimes it even crashes. If you ex...")
 
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In case of a problem with COMSOL on one of our clusters, please first contact the cluster support. We have very good relations to the COMSOL support and if we cannot solve a problem, we will open a ticket at the COMSOL support and add the user to this ticket, such that he also gets the answers from COMSOL support.
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===Problems with the COMSOL 5.2 GUI===
 
===Problems with the COMSOL 5.2 GUI===
  

Revision as of 06:25, 24 August 2016

In case of a problem with COMSOL on one of our clusters, please first contact the cluster support. We have very good relations to the COMSOL support and if we cannot solve a problem, we will open a ticket at the COMSOL support and add the user to this ticket, such that he also gets the answers from COMSOL support.

Problems with the COMSOL 5.2 GUI

We noticed, that in some cases, the COMSOL 5.2 GUI updates very slowly when staring it on Euler or sometimes it even crashes. If you experience this kind of problem, then you can try to start the COMSOL GUI with the following option:

comsol -3drend sw

If the problem still persists, the reason could be that you are on a login node, which is overloaded. We recommend in this case to log out and log in to the cluster again.

Too many threads

For comsol/4.4 and newer version, we observed a problem with regards to hybrid parallel jobs (OpenMP/MPI).

 bsub -n X [LSF-parameters] comsol batch -clustersimple -np Y -inputfile infile.mph -outputfile outfile.mph

will be interpreted as a job with X MPI processes, and each one spawning Y threads (OpenMP). LSF will reserve X job slots, but the job will start X*Y threads in total, which is very inefficient because the compute node will be overloaded with threads. Therefore we do not yet support hybrid COMSOL jobs on our clusters. Please do not start hybrid parallel COMSOL jobs when using comsol/4.4 or newer versions.

The correct syntax for distributed and shared memory parallel jobs can be found on this wiki page.